Co-star Holliday Grainger explains the audience can make their own conclusions on the movie.

Sam Claflin felt like a lost teenager again while making My Cousin Rachel.

The British actor may be 30 years old but he allowed himself to be transported back to his youth for the new mystery movie, based on the Daphne du Maurier novel about a man called Philip who suspects his cousin, played by Rachel Weisz, killed his guardian.

But as Philip grows to know Rachel more he unwillingly falls under her spell, a scenario Sam was all too familiar with having experienced the same uncertainty years ago before marrying wife Laura Haddock in 2013.

“It reminded me massively of being a teenager in love and not knowing. ‘Oh, she put two kisses at the end of a message, that means she wants to sleep with me!’” he laughed to Total Film magazine. “The things you read into any given moment – not knowing if you’re in or not.”

Also starring in the movie is Holliday Grainger as Louise, Philip’s friend who helps him investigate whether Rachel was responsible for the deadly crime. Not giving anything away about the plot, the 29-year-old explained the film has a ‘did she/didn’t she’ vibe to it that lets viewers guess themselves.

“You make your own conclusions,” she said. “It’s almost like giving the audience power in the way that whatever their conclusion is, it’s right. I feel like if this was a first-date film, it might cause an argument!”

To sum it up, Holliday compares it to David Fincher’s adaptation of Gillian Flynn’s best-selling novel Gone Girl - but with more mystery.

Rachel was also a fan of the fact that the truth of her character was kept secret, noting: “You just never know. I guess that’s the simplest way... You just never know.”